Unit dose detergent products are often found by consumers to be preferable for use in automatic dishwashing and laundry applications. Such unit dose products have several advantages, including convenience of use and dispensing, lower cost per use, and avoiding or minimizing skin contact with potentially irritating cleaning compositions.
In unit dose formulations with high solvent content, e.g., over 30% wt of total added solvent on the weight of the entire formulation, it is difficult to maintain pack rigidity in multi-chamber products using polyvinyl alcohol (PVOH) or polyvinyl acetate (PVA) film. With increased solvent content, the weight of the liquid composition in the compartment of multi-chamber product makes it ‘sag’ down, making the unit dose composition appear ‘floppy’. Moreover, such unit dose compositions may suffer from unexpected rupturing. This is due to the weight of one compartment putting undue load pressure on the film causing it to overstretch and rupture which will lead to leakage or breakage.
Traditional formulas have included a total of three solvents. The most commonly used solvent system includes water, glycerin, and propylene glycol. Recently, an ionic liquid has also been employed as a solvent.
There remains a need in the art for a unit dose composition with high solvent content while maintaining pack integrity such as rigidity and stability.
It was surprisingly found that employing a solvent system that employs at least five solvents, e.g., glycol ethers, polyethylene glycols, or diols, stabilizes the unit dose system and enhances rigidity to an acceptable level despite the much higher solvent content. This invention shows the benefit of a structured solvent system with five different solvents and how it improves pack rigidity (i.e. height) by up to 15%, which is extremely significant. Overall benefit to the consumer is a more stable unit dose pack that is less prone to leakage or breakage, and one that is more aesthetically pleasing during handling.